Date: Wed, 26 Mar 2003 12:18:40 -0800 (PST) From: Robert Watson <rwatson@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/kern kern_malloc.c src/sys/conf options Message-ID: <200303262018.h2QKIe5u044123@repoman.freebsd.org>
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rwatson 2003/03/26 12:18:40 PST
FreeBSD src repository
Modified files:
sys/kern kern_malloc.c
sys/conf options
Log:
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles
in a debugging feature causing M_NOWAIT allocations to fail at
a specified rate. This can be useful for detecting poor
handling of M_NOWAIT: the most frequent problems I've bumped
into are unconditional deference of the pointer even though
it's NULL, and hangs as a result of a lost event where memory
for the event couldn't be allocated. Two sysctls are added:
debug.malloc.failure_rate
How often to generate a failure: if set to 0 (default), this
feature is disabled. Otherwise, the frequency of failures --
I've been using 10 (one in ten mallocs fails), but other
popular settings might be much lower or much higher.
debug.malloc.failure_count
Number of times a coerced malloc failure has occurred as a
result of this feature. Useful for tracking what might have
happened and whether failures are being generated.
Useful possible additions: tying failure rate to malloc type,
printfs indicating the thread that experienced the coerced
failure.
Reviewed by: jeffr, jhb
Revision Changes Path
1.384 +1 -0 src/sys/conf/options
1.120 +26 -0 src/sys/kern/kern_malloc.c
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